Preprints
https://doi.org/10.5194/tc-2021-186
https://doi.org/10.5194/tc-2021-186

  26 Aug 2021

26 Aug 2021

Review status: this preprint is currently under review for the journal TC.

Relationships between Andean Glacier Ice-Core Dust Records and Amazon Basin Riverine Sediments

Rafael S. dos Reis1, Rafael da Rocha Ribeiro1, Barbara Delmonte2, Edson Ramirez3, Norberto Dani1, Paul A. Mayewski4, and Jefferson C. Simões1,4 Rafael S. dos Reis et al.
  • 1Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91501-970, Brazil
  • 2Environmental and Earth Sciences Department, University Milano-Bicocca, Milan, 20126, Italy
  • 3Instituto de Hidráulica e Hidrología, Universidad Mayor de San Andrés, La Paz, Bolivia
  • 4Climate Change Institute, University of Maine, Orono, ME 04469, USA

Abstract. Dust particle studies in ice cores from the tropical Andes provide important information about climate dynamics. We investigated dust concentrations from a 22.7 m ice-core recovered from the Quelccaya Ice Cap (QIC) in 2018, representing 12 years of snow accumulation. The dust seasonality signal was still preserved with some homogenization of the record due to surface melting and percolation. Using a microparticle counter, we measured the dust concentration from 2–60 µm and divided the annual dust concentration into three distinct groups: fine particle percentage (FPP, 2–10 µm), coarse particle percentage (CPP, 10–20 μm) and giant particle percentage (GPP, 20–60 μm). Increased dust was associated with the warm stage of the Pacific Decadal Oscillation index (PDO) from 2014–2017 with significant increases in FPP and a relative decrease in GPP. There was a positive correlation between PDO and FPP (r = 0.68, p-value < 0.02). CPP and GPP were dominant during the PDO cold phase (2005–2013) and were more strongly associated with the Tropical Northern Atlantic index (TNA), which was positive from 2005–2017. The relation between TNA and CPP was r = 0.60 (p-value < 0.05) and that with GPP was r = 0.59 (p-value < 0.05). We also revealed a potential link between QIC dust and Madeira River sediments and runoff. Sediment concentration decreases at Porto Velho station were correlated with %GPP (r = 0.67, p < 0.02) from 2005–2017. This relationship contributes to a better understanding of the effects of PDO oscillations on both parameters. The %GPP and sediment decreases were potentially linked with the PDO phase change from negative to positive. We also noted a strong negative correlation between FPP and runoff (r = −0.80, p < 0.002) from 2005–2016, which was understandable due to the relationship of FPP to wetter conditions while runoff decreases were associated with increasing dryness in the southern part of the Madeira Basin. Assessing dust record variability by distinct size groups can help to improve our knowledge of how the Pacific and Atlantic oceans influence atmospheric oscillations in the QIC. In addition, the association of dust variability with dynamic changes in sediments and runoff in the Madeira River system demonstrates the potential for future investigation of linkages between QIC dust and Amazon basin rivers.

Rafael S. dos Reis et al.

Status: open (until 21 Oct 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Rafael S. dos Reis et al.

Rafael S. dos Reis et al.

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Short summary
The ice-core recovered in Peruvian Andes depicts the 12 years of dust particles data in snow accumulation. The seasonality of the dry and wet season, respectively, are represented by high and low dust concentration in profile. Our observations period show the differences between fine and larger particles concentrations over the years and their correlation with oceanic oscillations phenomena. Also, we introduce the link of the dust groupings with Madeira River in the Amazon basin context.